Balanced staple food for koi for year-round feeding sera KOI ROYAL is a balanced staple food and perfectly tailored to the nutritional requirements of koi and other pond fish. It promotes healthy growth and is highly digestible. The balanced content of natural minerals, trace elements and vitamins strengthens the immune system and ensures vital fish. According to the stages of development of the Koi, the feed is available in three grain sizes MINI (2 mm), MEDIUM (4 mm) and LARGE (6 mm).